Method and computer program for the detection of the contour of an obstacle in the surroundings of a vehicle

ABSTRACT

The invention relates to a method for detecting the contour of an obstacle in the surroundings of a moving vehicle by means of a sensor device that is preferably integrated in the lateral area of the vehicle. In previously known methods of this type, the sensor device usually emits a sensor signal to the obstacle already when said obstacle lies ahead in the direction of travel while also emitting a sensor signal once the vehicle has passed the obstacle. In order to improve evaluation of the sensor signals with regard to the reflection thereof on the obstacle, the reflection signals thus generated are first mathematically averaged so as to be able to then derive in a more precise manner the actual position and the actual shape of the contour of the obstacle from the obtained averaged reflection signal.

This application is the national stage of PCT/EP2004/007507 filed onJul. 8, 2004 and also claims Paris Convention priority of DE 103 43331.7 filed on Sep. 12, 2003.

BACKGROUND OF THE INVENTION

The invention relates to a method and a computer program for detectingthe contour of an obstacle in the surroundings of a moving vehicle usinga sensor means which is preferably disposed in a side area of thevehicle. The invention also relates to a computer program and a parkingspace detecting device for performing this method.

A parking aid for vehicles is conventionally known, in particular fromDE 101 46 712 A1. It comprises two distance sensors providing two sensorsignals of different beam geometries, which generate together adirectional characteristic with a cross lobe. These sensor means arepreferably disposed in the side area of a vehicle. In this cross lobeconfiguration, one of the sensors has a wide beam lobe in a horizontaldirection and a narrow beam lobe in a vertical direction. When thevehicle passes an obstacle, at least the following steps are performed:

Emitting a first sensor signal by the sensor means in one directionhaving a directional portion that lies in the direction of travel of thevehicle, when the obstacle is ahead of the vehicle in the travellingdirection.

Receiving at least part of the first sensor signal after reflectionthereof on the obstacle in the form of a first reflection signal whichrepresents a first position and a first shape of the contour of theobstacle;

Emitting a second sensor signal by the sensor means in a directionhaving a directional portion that is opposite to the direction of travelof the vehicle, when the vehicle has passed the obstacle;

Receiving at least part of the second sensor signal after reflectionthereof on the obstacle in the form of a second reflection signal whichrepresents a second position and a second shape of the contour of theobstacle; and/or

Emitting a third sensor signal by the sensor means in a directionsubstantially perpendicular to the direction of travel when the passingvehicle is at the position of the obstacle; and

Receiving at least part of the third sensor signal after reflectionthereof on the obstacle in the form of a third reflection signal whichrepresents a third position and third shape of the contour of theobstacle.

DE 101 46 712 evaluates, in particular, the amplitudes of the reflectionsignals of the two sensor means which are received when the vehicle ispassing the obstacle. The evaluation thereof gives information about theposition and shape of the contour of the obstacle.

Departing from the above-mentioned prior art, it is the object of theinvention to further develop a conventional method and computer program,as well as a conventional parking space detecting device for detectingthe contour of an obstacle in the vicinity of a moving vehicle in such amanner that the position and/or the shape of the contour of the obstaclecan be recognized with more precision.

SUMMARY OF THE INVENTION

This object is achieved by the method of the independent claims. To bemore precise, the solution of the above-described method lies in thefollowing characterizing steps: generating an averaged reflection signalthrough mathematical, preferably arithmetical, averaging of at least twoof the reflection signals and through evaluation of the averagedreflection signal towards extracting the actual position and/or theactual shape of the contour of the obstacle.

Each individual reflection signal provides rough information about theposition and the shape of the contour of the obstacle. The informationconcerning the position and shape provided by the individual reflectionsignals only presents a rough indication of the actual position and theactual shape and usually does not exactly correspond therewith. However,the claimed mathematical averaging of at least two of the reflectionsignals advantageously provides significantly more precise informationabout the actual position and/or the actual shape of the contour of theobstacle. In principle, the at least two reflection signals used foraveraging may be arbitrarily selected. It is, however, recommended toconsider, in any case, the third reflection signal for averaging, sinceit provides very precise conclusions per se about the actual positionand the actual shape of the contour of the obstacle.

Further precision can be achieved through suitable weighting of thereflection signals used for mathematical averaging.

The first and second and optionally also third sensor signalsfundamentally lie in one plane. The claimed method detects onlyobstacles which are intersected by the plane. To detect a possiblechange of the contour shape of the obstacle in the vertical direction,the detection plane can advantageously be inclined relative to its anglewith respect to a fictitious vertical plane in the travelling directionof the vehicle and perpendicular to the street surface on which thevehicle is travelling.

The inventive method is advantageously suited for radar, ultrasound orlaser light signals.

Further advantageous embodiments of the method are the subject matter ofthe dependent claims.

The above-mentioned object of the invention is moreover achieved by acomputer program and a parking space detecting device for performing theclaimed method. The advantages of these solutions correspond to theadvantages mentioned above with reference to the claimed method.

BREIF DESCRIPTION OF THE DRAWING

The description includes a total of eight figures, wherein

FIG. 1 shows an obstacle in the detection range of a sensor means havinghorizontal emission characteristics, which is installed in a passingvehicle;

FIG. 2 a shows different examples of the contour of an obstacle whichwould be determined from different reflection signals;

FIG. 2 b shows the actual contour of the obstacle in comparison with theshape of the obstacle on the basis of an evaluation of a reflectionsignal averaged in accordance with the invention;

FIG. 3 a shows a vehicle passing a first obstacle and comprising asensor means that emits in different planes;

FIG. 3 b shows a vehicle passing a second obstacle and comprising asensor means that emits in different planes;

FIG. 4 a shows a vehicle passing an obstacle which is stepped in thevertical direction;

FIG. 4 b shows averaged reflection signals obtained while passing theobstacle shown in FIG. 4 a; and

FIG. 4 c shows a reconstruction of the contour of the obstacle of FIG. 4a, which is stepped in a vertical direction.

DESCRIPTION OF THE PREFERRED EMBODIMENT

The invention is described in detail below using different embodimentswith reference to the above-mentioned figures.

FIG. 1 shows an initial situation for performing the present invention.It shows a vehicle 200 passing an obstacle 300 in the travellingdirection F, in particular a parked vehicle. A parking space detectingdevice is installed in a side area of the passing vehicle 200, whichcomprises a sensor means 110 for emitting sensor signals and forreceiving reflection signals, and an evaluation means 120 for evaluatingthe reflection signals.

In accordance with the invention, this parking space detecting devicefunctions as follows: At least one first sensor signal is emitted by thesensor means 110 towards the obstacle 300 with a directional portionthat lies in the travelling direction F of the vehicle, preferably aslong as the obstacle 300 is opposite to and ahead of the vehicle 200 inthe travelling direction F. The sensor signal is reflected at theobstacle 300 and at least part of this first sensor signal is thenreceived by the sensor means 110 in the form of a first reflectionsignal. The first sensor signal represents a first position x1 and afirst shape V1 of the contour of the actual obstacle 300.

After the vehicle has passed the obstacle, the sensor means 110 sends asecond sensor signal towards the obstacle 300 having a directionalportion opposite to the direction of travel of the vehicle 200. At leastpart of this second sensor signal, which is reflected by the obstacle300, is received by the sensor means 110 in the form of a secondreflection signal. The second reflector signal R2 thereby represents asecond position x2 and a second shape V2 of the contour of the obstacle300. Since the two positions x1 and x2 represented by the two reflectionsignals, and the two contour shapes V1 and V2, taken alone, areinsufficient to represent the actual relationships, they aremathematically, preferably arithmetically, averaged in accordance withthe invention.

The averaged reflection signal R obtained in this manner represents theactual position x and the actual shape V of the contour of the obstacle300 much better than the values obtained from the first or secondreflection signal alone. This is shown in FIG. 2 b, wherein the dashedblack line shows the shape represented by the averaged reflection signalR and the fully drawn black line represents the actual position andactual shape of the contour of the obstacle 300.

A further substantial improvement in the actual position x and theactual contour shape V of the obstacle can be obtained if, in additionto the first and second reflection signals, a third reflection signal R3is also used for averaging. To obtain the third reflection signal, athird sensor signal is emitted by the sensor means 110 in a directionsubstantially perpendicular to the direction of travel F and towards theobstacle 300 when the vehicle is at the position of the obstacle 300.The third reflection signal R3 then represents at least part of thisthird sensor signal after being reflected from the obstacle 300. Thethird reflection signal R3 is preferably averaged with a higherweighting factor than the first and second reflection signals, since ithas turned out to represent more realistic information about theposition and the contour of the obstacle 300 compared to the first andsecond sensor signals. The first and second reflection signals arepreferably averaged with the same weighting.

As described above, it is a prerequisite of the present invention thatthe obstacle 300 is in the detection range of the sensor means 110 whenit is ahead of the vehicle 200 in the travelling direction, and alsowhen the vehicle 200 has already passed the obstacle. The first, secondand preferably also third sensor signals or reflection signals cantherefore be regarded as substantially being in one plane, as indicatedin FIG. 1.

FIG. 3 a shows shape profiles of different angular orientations of thisplane, in side view. All possible angular plane orientations E-1 . . .-N shown therein differ in position by a differing angle α-1 . . . -Nrelative to a fictitious vertical plane E_(v), which extends in thetravelling direction of the vehicle 200, perpendicular to a road surface250 on which the vehicle is travelling. If the parking space detectingdevice is designed such that it emits the sensor signals only in one ofthese planes E-1 . . . N, the inventive method also detects only thoseobstacles 300 which are intersected by the respective plane. In FIG. 3a, the obstacle 300 is intersected e.g. by the planes E-4 and E-5. Incontrast thereto, the obstacle 300′ shown in FIG. 3 b having a smallerheight would not be detected if the sensor means is oriented in theplane E-4 but would be detected if it were oriented in plane E-5.

In order to be able to precisely detect obstacles 300 of differentheights, the sensor means 110 is advantageously designed such that thesensor signals are emitted not only in one plane but in several planesE-1 . . . -N, either simultaneously or temporally offset. When thevehicle 200 passes a stepped obstacle 300″ in the travelling direction F(FIG. 4 a), the stepped contour shape of the obstacle 300″ can bedetected with the respective positions of the contours using a sensormeans 110 emitting in three dimensions. During application of theinventive method, several reflection signals, in particular, the first,second and third reflection signals are received for each flank 310″,320″ and 330″ of the stepped obstacle 300″, and are subsequentlyaveraged in accordance with the inventive method. The averagedreflection signals R310″, R320″, R330″ represent the actual positionsx11 . . . to x17 of the flanks of the stepped obstacle 300″ to a goodapproximation. The shapes shown in FIG. 4 b of the averaged reflectionsignals are obtained by emitting the first, second and/or third sensorsignal in different respective planes E-1 . . . -N. Evaluation of theangle information α-1 . . . -N by which the positions of the planes ofFIG. 4 b differ, permits reconstruction of both the separations x11 . .. x17 as well as the contour of the stepped obstacle 300″ in a verticaldirection. In this manner, it is possible to reconstruct, in particular,the heights h1 . . . -6 of the obstacle 300″.

The sensor means 110 for performing the inventive method must bedesigned to at least emit sensor signals in one of the planes E-1 . . .-N. Advantageously, it can also emit the sensor signals in a thirddimension, represented by the angles α-1 . . . N. Towards this end, itis preferably designed as multi-beam or scanner system.

The inventive method is preferably realized in the form of a computerprogram. The computer program for a parking space detecting device isstored, possibly together with further computer programs, on a datacarrier which can be read by a computer. The data carrier may be a disk,a compact disk, a so-called flash-memory or the like. The computerprogram stored on the data carrier can then be transferred and sold to acustomer in the form of a product. The computer program can betransferred and sold to a customer even without a physical data carrier,e.g. via a communications network, in particular, the internet.

1. A method for detecting a contour of an obstacle in a vicinity of amoving vehicle using a sensor means preferably installed in a side areaof the vehicle, the method comprising steps of: a) emitting a firstsensor signal, using the sensor means, in a direction having adirectional portion in a travelling direction of the vehicle when theobstacle is ahead of the vehicle in the travelling direction; b)receiving at least part of the first sensor signal after reflectionthereof from the obstacle, in a form of a first reflection signal thatrepresents a first position and a first shape of a contour of theobstacle; c) emitting a second sensor signal, using the sensor means, ina direction having a directional portion opposite to the travellingdirection of the vehicle when the vehicle has passed the obstacle; d)receiving at least part of the second sensor signal, after reflectionthereof from the obstacle, in a form of a second reflection signal thatrepresents a second position and a second shape of the contour of theobstacle; e) generating an averaged reflection signal throughmathematical or arithmetical averaging of the first and the secondreflection signals; and f) evaluating an averaged reflection signal toextract an actual position and actual shape of the contour of theobstacle.
 2. The method of claim 1, wherein the sensor signals are radarsignals, ultrasound signals, or laser light signals.
 3. A computerreadable medium having a program code, the computer program code beingdesigned for performing the method of claim
 1. 4. The computer readablemedium of claim 3, wherein a parking space is detected.
 5. A method fordetecting a contour of an obstacle in a vicinity of a moving vehicleusing a sensor means preferably installed in a side area of the vehicle,the method comprising steps of: a) emitting a first sensor signal, usinga sensor means, in a direction having a directional portion in atravelling direction of the vehicle when the obstacle is ahead of thevehicle in the travelling direction; b) receiving at least part of thefirst sensor signal after reflection thereof from the obstacle, in aform of a first reflection signal that represents a first position and afirst shape of a contour of the obstacle; c) emitting a second sensorsignal, using the sensor means, in a direction having a directionalportion opposite to the travelling direction of die vehicle when thevehicle has passed the obstacle; d) receiving at least part of thesecond sensor signal, after reflection thereof from the obstacle, in aform of a second reflection signal that represents a second position anda second shape of the contour of the obstacle; e) emitting a thirdsensor signal, using the sensor means, in a direction substantiallyperpendicular to the travelling direction when the vehicle is located ata substantially same position as the obstacle; f) receiving at leastpart of the third sensor signal, after reflection thereof from theobstacle, in a form of a third reflection signal that represents a thirdposition and a third shape of the contour of the obstacle; g) generatingan averaged reflection signal through mathematical or arithmeticalaveraging of at least two of the first, second and third reflectionsignals; and h) evaluating an averaged reflection signal to extract anactual position and actual shape of the contour of the obstacle.
 6. Themethod of claim 5, wherein the first, second and third reflectionsignals are used with individual weighting factors in averaging inaccordance with step g).
 7. The method of claim 6, wherein the thirdreflection signal is weighted more than the first and second reflectionsignals.
 8. The method of claim 7, wherein the first and the secondreflection signals are weighted by a same amount.
 9. The method of claim5, wherein the first, second and third reflection signals aresubstantially co-planar.
 10. The method of claim 9, further comprisingrepeating steps a) through h) for different angular positions of a planerelative to a vertical plane in a longitudinal direction of the vehicle.11. The method of claim 5, wherein the first, second and third sensorsignals are emitted at a substantially same time.
 12. A vehicle parkingspace detecting device to detect a contour of an obstacle in asurroundings of the vehicle and while the vehicle is moving, the devicecomprising: a) means for emitting a first sensor signal, using thesensor means, in a direction having a directional portion in atravelling direction of the vehicle when the obstacle is ahead of thevehicle in the travelling direction; b) means for receiving at leastpart of the first sensor signal after reflection thereof from theobstacle, in a form of a first reflection signal that represents a firstposition and a first shape of a contour of the obstacle; c) means foremitting a second sensor signal, using the sensor means, in a directionhaving a directional portion opposite to the travelling direction of thevehicle when the vehicle has passed the obstacle; d) mean for receivingat least part of the second sensor signal, after reflection thereof fromthe obstacle, in a form of a second reflection signal that represents asecond position and a second shape of the contour of the obstacle; e)means for generating an averaged reflection signal through mathematicalor arithmetical averaging of the first and the second reflectionsignals; and f) means for evaluating an averaged reflection signal toextract an actual position and actual shape of the contour of theobstacle.